$OpenBSD: patch-igmpproxy_c,v 1.2 2016/12/23 13:44:31 rzalamena Exp $
--- igmpproxy.c.orig	Thu Dec 15 19:50:24 2016
+++ igmpproxy.c	Thu Dec 15 19:51:46 2016
@@ -41,8 +41,8 @@
 #include "version.h"
 #include "build.h"
 
+#include <sys/sysctl.h>
 
-
 // Constants
 static const char Version[] = 
 "igmpproxy, Version " VERSION ", Build" BUILD "\n"
@@ -80,7 +80,7 @@
 *   on commandline. The number of commandline arguments, and a
 *   pointer to the arguments are recieved on the line...
 */    
-int main( int ArgCn, const char *ArgVc[] ) {
+int main( int ArgCn, char *ArgVc[] ) {
 
     int debugMode = 0;
 
@@ -133,6 +133,24 @@
     	exit(1);
     }
 
+    {
+	int ipmforwarding = 0;
+	int mib[4];
+	size_t len;
+
+        /* multicast IP forwarding must be enabled */
+        mib[0] = CTL_NET;
+        mib[1] = PF_INET;
+        mib[2] = IPPROTO_IP;
+        mib[3] = IPCTL_MFORWARDING;
+        len = sizeof(ipmforwarding);
+        if (sysctl(mib, 4, &ipmforwarding, &len, NULL, 0) == -1)
+	    log(LOG_ERR, 0, "sysctl");
+
+        if (!ipmforwarding)
+	    log(LOG_ERR, 0, "multicast IP forwarding not enabled");
+    }
+
     // Write debug notice with file path...
     IF_DEBUG log(LOG_DEBUG, 0, "Searching for config file at '%s'" , configFilePath);
 
@@ -155,17 +173,8 @@
         if ( ! debugMode ) {
     
             IF_DEBUG log( LOG_DEBUG, 0, "Starting daemon mode.");
-    
-            // Only daemon goes past this line...
-            if (fork()) exit(0);
-    
-            // Detach deamon from terminal
-            if ( close( 0 ) < 0 || close( 1 ) < 0 || close( 2 ) < 0 
-                 || open( "/dev/null", 0 ) != 0 || dup2( 0, 1 ) < 0 || dup2( 0, 2 ) < 0
-                 || setpgrp() < 0
-               ) {
+            if ( daemon(1, 0) < 0)
                 log( LOG_ERR, errno, "failed to detach deamon" );
-            }
         }
         
         // Go to the main loop.
@@ -218,7 +227,9 @@
         int     vifcount = 0;
         upStreamVif = -1;
 
-        for ( Ix = 0; Dp = getIfByIx( Ix ); Ix++ ) {
+        for ( Ix = 0; (Dp = getIfByIx( Ix )); Ix++ ) {
+		if (config_getinterface(Dp->Name) == NULL)
+			continue;
 
             if ( Dp->InAdr.s_addr && ! (Dp->Flags & IFF_LOOPBACK) ) {
                 if(Dp->state == IF_STATE_UPSTREAM) {
@@ -237,7 +248,7 @@
 
         // If there is only one VIF, or no defined upstream VIF, we send an error.
         if(vifcount < 2 || upStreamVif < 0) {
-            log(LOG_ERR, 0, "There must be at least 2 Vif's where one is upstream.");
+            log(LOG_ERR, 0, "There must be at least 2 Vif's where one is upstream. (vifcount %d, upStreamVif %d)", vifcount, upStreamVif);
         }
     }  
     
